1. Field of the Invention
The invention relates to a lockup clutch with a torsional vibration damper for use with a torque converter.
2. Description of the Related Art
A prior art lockup clutch having a torsional vibration damper for use with a torque converter is shown in German reference DE 41 35 631 A1. The prior art lockup clutch includes an axially deflectable piston through which torque can be transmitted from a drive side of the torque converter to an output side of the torque converter, which comprises a turbine wheel of the torque converter. The torsional vibration damper includes an input part, and output part, and energy storage devices disposed therebetween. The piston is connected to the input part of a torsional vibration damper which serves as a cover element for the energy storage devices effective between the input and output parts. The input part is open on its side facing the output part of the torsional vibration damper for accommodating the energy storage devices. The energy storage devices are radially secured in the cover element between two radial supports. An axial support that connects the radial supports to each other axially secures the energy storage devices against movements directed toward the piston. The energy storage device region that faces the open side of the cover element can be axially secured by the output part of the torsional vibration damper, whereby the output part penetrates between the radial supports of the cover element with predetermined depth.
The outer radial support has control elements in the form of divided brackets curved toward the energy storage devices. In contrast, the inner support consists of brackets curved out from a section that serves to attach the cover element to the piston. Further control elements for the energy storage devices are curved out from the same section.
A torsional vibration damper embodied on the lockup clutch in this fashion makes optimal use of the axial structural space available between the piston and turbine wheel in the radial outer area. However, because the control elements are separated from the outer radial support, the latter is not strong enough to provide sufficient resistance against the centrifugally-induced radial forces transmitted by the energy storage devices. Therefore, a plastic deformation of the outer radial support of the cover element must therefore be expected. For this reason, a collar encircles the outer radial support on the circumferential area of the piston. The result of this measure is to move the energy storage devices farther radially inward. This is undesired, however, because for transmitting very high torques, the energy storage devices must be arranged in the outermost radial area. Otherwise, the energy storage devices must be embodied in a sufficiently long-stroked fashion to yield the desired damping properties.
To avoid limiting the available space even further, the control elements on the input-side and output-side components of the torsional vibration damper are kept so short that the energy storage devices are not pressurized over their entire width, but only by a smaller area. As a result, the pressure exerted on these small areas of contact on the energy storage device and the control elements is high. Therefore, premature wear results.